1. Field of the Invention
The present invention relates to a high-insulated stud and in further detail, to a high-insulated stud that connects multiple reed relays and a printed circuit board (printed board) that uses this high-insulated stud.
2. Description of the Prior Art
The technology disclosed in Utility Model Laid-Open No. Sho 63(1988)-73,836 shown in FIG. 1 is known as a conventional high-density, high-insulation mounting method by means of which multiple relays housing multiple reed switches are connected.
An example is shown in FIG. 1 where reed relay 3 houses reed switches in 3 vertical rows and 4 horizontal rows and the reeds at positions corresponding to adjacent relays themselves are connected. The highest reeds bend away slightly to the left and the second-highest reeds bend away slightly to the right. Metal conductors 41 and 42 with an extension at appropriate heights and spacing for each reed of the multiple relays are soldered to the reeds.
Metal conductors 41 and 42 are anchored by insulation member 44 to the printed board. The insulation holds metal conductors 41 and 42 with polyester film (not illustrated) in between.
By means of this technology, mounting density is improved somewhat, but a special relay is used and therefore, cost is increased. Moreover, the heights and spacing of the extensions of the metal conductors used to connect relays is determined from the layout of each part and the board, and therefore, there are problems in that it is difficult to make universal parts and cost is increased. Furthermore, the metal conductors trail a long distance close to the board and therefore, there is an increase in parasitic capacitance and a reduction in noise property.
As an example of a different prior art, relays have been mounted by the method shown in FIG. 2 when signal conductors are present for which high-insulation must be guaranteed, but it was not necessary to mount as many relays and when it was preferred that cost be kept down using universal parts.
This is described in FIG. 2 using a 2-reed relay as an example. Lead 218 extending from the reed switch on one side of 2-reed relay 214 is a signal conductor for which high-insulation must be guaranteed. Lead 218 trails in the groove part of high-insulated stud 222, such as a Teflon stud, etc., in order to connect to other signal conductors. Precautions should be taken here so that the other signal conductors to be disconnected are wired aerially in order to guarantee high-insulation. Incidentally, Teflon studs (Teflon terminals), such as FX-3 made of MAC8, etc., are known as high-insulated studs.
Moreover, relays such as URM-P22912GTE made by Sanyu Co., Ltd., etc., are known as 2-reed relays. It is also common knowledge that depending on their purpose, the make-contact type or transfer-contact type of these relays is used.
Lead 216 that extends from the reed switch on the other side of each 2-reed relay 214 is used as a guard line for shielding the above-mentioned signal conductor and is bent at the end of the relay terminal and soldered to land 220 of the printed board 212 in order to be connected to the guard pattern on the printed board.
When each high-insulated stud 222 is connected for multi-channel connection, lead 218 is trailed through the groove part and then connecting lead 224, such as tin-plated wires, etc., is coiled around one (226b) of top parts 226a and 226b where each stud branches in two and eventually are soldered.
There are the following problems when this prior art is used:
First, the work involving coiling lead 224 around this top part 226b is quite delicate, and therefore, working cost is increased, because a columnar high-insulated stud as small as 3 millimeters in diameter is generally used for efficient use of surface area.
Next, in order to guarantee working space of high-insulated stud 222, the stud must be as much as length L1+L2 from land 220. However, the surface area that is occupied will increase and mounting efficiency will drop. In the example in FIG. 2, L1 is clearance from the end of the guard pipe of the relay to where lead 216 connects with land 220 and is 4 mm and L2 is the distance from the outside rim of high-insulated stud 222 to land 220 and is 6 mm. Therefore, a space of 3 to 5 mm is needed as the clearance for bending wiring 224 horizontally between multiple high-insulated studs 222. In conclusion, by means of this technology, a total length of 13 to 15 mm from the end of the guard pipe of the relay is occupied.
Third, because the work involved in bending guard lead 216 to the position on land 220 is a delicate operation, working cost is increased. Cracks are made in the glass tube in which the reed switches have been inserted by the tools used to apply pressure and as a result, the percent of defective units increases.
The present invention solves the above-mentioned problems, its purpose being to present a high-insulated stud and printed board holding the same with which mounting density is raised while guaranteeing high-insulation performance and high voltage tolerance and a reduction in the number of processes involved in mounting and improved working performance, as well as a reduction in parasitic capacitance and prevention of cracking of the glass tube in which reed switches have been inserted, are expected.
The high-insulated stud of a first embodiment of the present invention comprises a first columnar conductive terminal having a first height, a second columnar conductive terminal having a second height lower than the height of said first conductive terminal that is placed in a row with and at a distance from said first conductive terminal, an insulating pedestal, a first groove open at the top, a second groove intersecting said first groove and shallower than said first groove at the top of said first conductive terminal, and a third groove open at the top, which is parallel with said first groove and whose bottom face is almost the same height as the bottom face of said first groove, at the top of said second conductive terminal.
Here, the second conductive terminal can also have a connection terminal that passes through said pedestal.
By means of a different embodiment, the second groove can be a groove open at the top, or the second groove can be a groove open sideways.
The printed circuit board with a high-insulated stud of another embodiment of the present invention comprises a first columnar conductive terminal placed at a first height on said board and insulated from said board by a first insulating member and a second columnar second terminal having a second height lower than the height of said first conductive terminal that is placed in a row with and at a distance from said first conductive terminal where said second conductive terminal connected to the circuit on said substrate, and a first groove open at the top and a second groove that intersects said first groove and that is shallower than said first groove at the top of said first conductive terminal and a third groove open at the top, which is parallel with said first groove and whose bottom face is almost the same height as the bottom face of said first groove, at the top of said second conductive terminal.
Another embodiment of the printed circuit board with a high-insulated stud is characterized in that it has a second insulation member around the outside of the base of the second conductive terminal.
Another embodiment of the printed circuit board with a high-insulated stud is characterized in that said first insulation member is also wrapped around the base of said second conductive terminal.
Yet another embodiment of the printed circuit board with a high-insulated stud comprises first and second columnar conductive terminals placed at a first height on said board and insulated together with said board by an insulation member and third and fourth columnar conductive terminals of a second height lower than the height of said first conductive terminal which are connected to the circuit on said board, said conductive terminals are each arranged in a row in the order of said first, third, second and fourth conductive terminals, there is a first groove open at the top and a second groove that intersects said first groove and is shallower than said first groove at the top of each of said first and second conductive terminals, there is a third groove open at the top that is parallel with said first groove and has a bottom face of approximately the same height as the bottom face of said first groove at the top of each of said third and fourth terminals, and the second grooves of said first and second terminals are connected by a metal wire.